The perfect pea?

A group of scientists at the John Innes Centre in the U.K. have developed peas that will help animals absorb more protein from their diet. Published in PLOS ONE, this study is important because peas and other legume seeds contain several proteins that stop nutrients from being fully absorbed in the intestines of not only poultry and livestock, but in humans as well.

One such class of molecule is the protease inhibitors, which slow down the rate of protein digestion by incapacitating the enzymes that break them down. For example, previous nutritional studies with broiler chickens have shown that peas with this molecule can reduce protein availability by up to 10% in the birds.

As explained in a recent article, Dr. Claire Domoney and her group of researchers identified and studied peas with mutations in genes coding for the seed protease inhibitors, known as the trypsin/chymotrypsin inhibitors. They found three types of mutation, one of which was in a wild relative of pea, and which completely wiped out the seed’s ability to inhibit protein digestion. The other two mutations were generated by mutagenesis and were also effective in reducing the inhibitors, although less dramatically so.

Dr. Domoney’s results provide proof of principle for the ways in which food and feedstuffs can be improved through large-scale genetic approaches as peas provide a valuable and nutritious crop for human and pet food and animal feed. The research can be extended to more proteins in pea and other legume crops, where food or feed use may be limited by the same or different seed proteins. Removal of allergenic proteins, for example, is an important goal for improving many food and feed crops.

“The discovery of a wild pea line, a Pisum elatius line from Turkey which lacks a protein defined as an ‘anti-nutrient’, is a clear example of the value of diverse germplasm collections. Being able to generate and/or discover genetic variation for traits of interest to growers is essential for improving crop traits,” Dr. Domoney said in the article. “In our case, the wild pea mutant has been crossed readily with the cultivated species, Pisum sativum, providing a head start for breeders. Mutagenized resources, such as that at INRA, are also an invaluable resource for novel variation. We are now in a good position with new technologies to be able to screen very large numbers of lines for small changes in genes of interest.”

Breeders are already showing interest in the new peas as non-GM methods were used, the article states. In fact, Dr. Domoney said she expects widespread adoption of the variant pea lines and that the novel peas could reach the market within five years.

“The value of genetics and targeted research in pulse crops aids the U.K. industry in achieving specific needs,” crop breeder Peter Smith said in the article. “The removal of inhibitors in peas is an example of one of many traits which should enable the industry to move forward with a nutritionally improved crop benefiting throughout the food chain.”